Account banned, and do not know how to send a support ticket (pls help)

My account was banned today after i played with three friends on the same wifi at the same time on a private game, my account is locked and i have been given the choice of picking one of the three accounts to save. I have been playing for almost a year now and this has never happened. i have looked for instructions on writing support tickets but have found none.I also do not know what proof i am supposed to give to save my account and friend's account.

If you can help in any way or guide me in the right direction on this issue, please reply.

Thank you,

BrandenburgMann